On Thu, 2008-02-28 at 16:43 +0900, Tejun Heo wrote: > Hello, all. > > Sorry about the delay. Was buried under other stuff. Mike, thanks a > lot for reporting and analyzing the problem; however, the patch is > slightly incorrect. rq->data_len is rq->data_len + extra stuff for > alignment and padding, so the correct thing to do is... > > req->raw_data_len -= req->data_len - scsi_get_resid(cmd); > req->data_len = scsi_get_resid(cmd); Ah, close but no banana. (feeds poor wingless patchlet to bit-wolf) > which is ugly and error-prone. In addition, this isn't the only place > where resid is set. Other block drivers do this too. This definitely > should be done in block layer. > > With rq->data_len and rq->raw_data_len, it's impossible to translate > resid of rq->data_len to resid of rq->raw_data_len as block layer > doesn't know how much was extra data after rq->data_len is modified. > The attached patch substitutes rq->raw_data_len w/ rq->extra_len and > adds blk_rq_raw_data_len(). Things look cleaner this way and the resid > problem should be solved with this. > > Can you please verify the attached patch fixes the problem? > > Thanks. Thank you, works fine. > plain text document attachment (patch) > diff --git a/block/blk-core.c b/block/blk-core.c > index 775c851..929ab61 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -127,7 +127,7 @@ void rq_init(struct request_queue *q, struct request *rq) > rq->nr_hw_segments = 0; > rq->ioprio = 0; > rq->special = NULL; > - rq->raw_data_len = 0; > + rq->extra_len = 0; > rq->buffer = NULL; > rq->tag = -1; > rq->errors = 0; > @@ -2016,7 +2016,6 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq, > rq->hard_cur_sectors = rq->current_nr_sectors; > rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio); > rq->buffer = bio_data(bio); > - rq->raw_data_len = bio->bi_size; > rq->data_len = bio->bi_size; > > rq->bio = rq->biotail = bio; > diff --git a/block/blk-map.c b/block/blk-map.c > index 09f7fd0..c67a75f 100644 > --- a/block/blk-map.c > +++ b/block/blk-map.c > @@ -19,7 +19,6 @@ int blk_rq_append_bio(struct request_queue *q, struct request *rq, > rq->biotail->bi_next = bio; > rq->biotail = bio; > > - rq->raw_data_len += bio->bi_size; > rq->data_len += bio->bi_size; > } > return 0; > @@ -156,6 +155,7 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq, > bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len; > bio->bi_size += pad_len; > rq->data_len += pad_len; > + rq->extra_len += pad_len; > } > > rq->buffer = rq->data = NULL; > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 7506c4f..efb5b4d 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -232,6 +232,7 @@ new_segment: > (PAGE_SIZE - 1)); > nsegs++; > rq->data_len += q->dma_drain_size; > + rq->extra_len += q->dma_drain_size; > } > > if (sg) > diff --git a/block/bsg.c b/block/bsg.c > index 7f3c095..81b2133 100644 > --- a/block/bsg.c > +++ b/block/bsg.c > @@ -437,14 +437,14 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, > } > > if (rq->next_rq) { > - hdr->dout_resid = rq->raw_data_len; > - hdr->din_resid = rq->next_rq->raw_data_len; > + hdr->dout_resid = blk_rq_raw_data_len(rq); > + hdr->din_resid = blk_rq_raw_data_len(rq->next_rq); > blk_rq_unmap_user(bidi_bio); > blk_put_request(rq->next_rq); > } else if (rq_data_dir(rq) == READ) > - hdr->din_resid = rq->raw_data_len; > + hdr->din_resid = blk_rq_raw_data_len(rq); > else > - hdr->dout_resid = rq->raw_data_len; > + hdr->dout_resid = blk_rq_raw_data_len(rq); > > /* > * If the request generated a negative error number, return it > diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c > index e993cac..32424b3 100644 > --- a/block/scsi_ioctl.c > +++ b/block/scsi_ioctl.c > @@ -266,7 +266,7 @@ static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr, > hdr->info = 0; > if (hdr->masked_status || hdr->host_status || hdr->driver_status) > hdr->info |= SG_INFO_CHECK; > - hdr->resid = rq->raw_data_len; > + hdr->resid = blk_rq_raw_data_len(rq); > hdr->sb_len_wr = 0; > > if (rq->sense_len && hdr->sbp) { > @@ -528,8 +528,8 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk, > rq = blk_get_request(q, WRITE, __GFP_WAIT); > rq->cmd_type = REQ_TYPE_BLOCK_PC; > rq->data = NULL; > - rq->raw_data_len = 0; > rq->data_len = 0; > + rq->extra_len = 0; > rq->timeout = BLK_DEFAULT_SG_TIMEOUT; > memset(rq->cmd, 0, sizeof(rq->cmd)); > rq->cmd[0] = cmd; > diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c > index 0562b0a..5cab84c 100644 > --- a/drivers/ata/libata-scsi.c > +++ b/drivers/ata/libata-scsi.c > @@ -2539,7 +2539,8 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc) > * want to set it properly, and for DMA where it is > * effectively meaningless. > */ > - nbytes = min(scmd->request->raw_data_len, (unsigned int)63 * 1024); > + nbytes = min(blk_rq_raw_data_len(scmd->request), > + (unsigned int)63 * 1024); > > /* Most ATAPI devices which honor transfer chunk size don't > * behave according to the spec when odd chunk size which > diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 6fe67d1..57e2a9e 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -216,8 +216,8 @@ struct request { > unsigned int cmd_len; > unsigned char cmd[BLK_MAX_CDB]; > > - unsigned int raw_data_len; > unsigned int data_len; > + unsigned int extra_len; > unsigned int sense_len; > void *data; > void *sense; > @@ -477,6 +477,11 @@ enum { > > #define rq_data_dir(rq) ((rq)->cmd_flags & 1) > > +static inline unsigned int blk_rq_raw_data_len(struct request *rq) > +{ > + return rq->data_len - min(rq->extra_len, rq->data_len); > +} > + > /* > * We regard a request as sync, if it's a READ or a SYNC write. > */ - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html